The present disclosure herein relates to a semiconductor memory device, and more particularly, to a flash memory device for improving repair efficiency and an operation method thereof.
A semiconductor memory device is a memory device that is implemented with semiconductors such as silicon (Si), germanium (Ge), gallium arsenide (GaAs) and indium phosphide (InP). Semiconductor memory devices can be categorized as either volatile memory devices or nonvolatile memory devices.
A volatile memory device is a memory device in which stored data is lost when a power source voltage is shut off. Some examples of volatile memory devices include: Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM) and Synchronous Dynamic Random Access Memory (SDRAM). A non-volatile memory device is a memory device that retains stored data even when a power source voltage is shut off. Some examples of non-volatile memory devices include: Read-Only Memory (ROM), Programmable Read Only Memory (PROM), Erasable Programmable Read Only Memory (EPROM), Electrical Erasable Programmable Read Only Memory (EEPROM), flash memory device, Phase-change Random Access Memory (PRAM), Magnetoresistive Random Access Memory (MRAM), Resistive Random Access Memory (RRAM) and Ferroelectric Random Access Memory (FRAM). The flash memory devices can be categorized as NOR type or NAND type.
A NOR type flash memory has a structure in which a plurality of cell transistors are connected to one bit line in parallel. The NOR type flash memory stores data in a channel hot electron scheme, and erases data in a Fowler-Nordheim (F-N) tunneling scheme. On the other hand, a NAND type flash memory has a string structure in which a plurality of cell transistors are serially connected to one bit line. The NAND type flash memory stores and erases data in the F-N tunneling scheme.